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        검색결과 1,070

        321.
        2016.04 구독 인증기관·개인회원 무료
        The objective of this study was to evaluate size-different chitosan nanoparticles as a CO2 indicator. CO2 gas is dissolved to form H2CO3 which makes the solution acidic. Chitosan is acid soluble and its appearance (turbidity) changes depending on pH in aqueous solution. Two size-different chitosan nanoparticles were fabricated by ionic gelation between chitosan (0.30 and 0.50%, w/v) and 0.07% sodium tripolyphosphate (TPP) solution. The sizes of chitosan nanoparticles were 630.77 and 1194.87 nm, respectively. To investigate the effect of chitosan nanoparticles as CO2 indicator, the initial pH of chitosan nanoparticle suspension was adjusted to 8.0. Thereafter, 100% CO2 gas was injected into the chitosan nanoparticle suspension, and the changes of pH and absorbance (600 nm of absorption wavelength) of the suspension over time were measured for 28 min. Absorbance at the appearance transition and its corresponding time was calculated using logistic function (R2> 0.99).As a result, pH of chitosan nanoparticle suspension decreased rapidly under CO2 gas injection for 10 min and finally reached around 6.0. In addition, there was significant difference in appearance transition time which was6.62 and 12.45 min for small- and large-sized chitosan nanoparticle suspensions, respectively. This study suggests that chitosan nanoparticle suspension might be useful as a food quality indicator for CO2 emitting foods such as fermented foods.
        324.
        2016.04 구독 인증기관·개인회원 무료
        Most ectotherms mature at a larger body size in colder conditions. This negative relationship between developmental temperature and final body size is termed the temperature-size rule. In this study, we investigated how dietary protein:carbohydrate (P:C) balance modulates the fundamental relationship between temperature and body size in the final-instar caterpillars of Spodoptera litura. The magnitude and sign of the thermal reaction norm for body size were altered by the dietary P:C balance of the food eaten by caterpillars. The slope of the reaction norm was flat for caterpillars raised on a nutritionally balanced food (P:C = 1:1) but was negative for those on imbalanced foods (1:5 or 5:1). When allowed to self-compose their preferred diet, caterpillars preferred carbohydrate-rich food at higher temperatures. The negative impact of high temperature on body size was mitigated by such a temperature-driven shift in nutrient preference. This study highlights the importance of macronutrient balance as a key factor modulating the relationship between temperature and body size in insects.
        325.
        2016.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목 적: 동공크기가 일정하게 증가할 때 나타나는 굴절력 변화를 측정하여 분석하였다. 방 법: 백내장이나 안질환 및 시력교정수술 등의 경력이 없는 근시 50명(100안), 원시 9명(17안)을 대상 으로 하였다. 암순응상태의 동공크기 검사는 Colvard pupillometer(OASIS medical, USA)를 사용하였다. 굴절력은 Zywave(Baush & Lomb, USA)를 사용하여 측정하였다. 동공크기가 3.0mm에서 6.0mm까지 0.5mm씩 증가할 때 굴절력 값을 분석하였다. 동공크기에 따른 굴절력 변화는 ANOVA를 사용하였고, 상관 분석을 하여 변수들 간의 연관성을 보았다. 결 과: 평균연령은 44.05±11.91세(25~64세), 암순응상태의 동공크기는 6.57±0.52mm로 나타났다. 나 이가 증가할수록 암순응상태의 동공크기가 작았다(p=0.000). 동공크기(3.0~6.0mm)에 따른 등가구면굴절 력의 변화는 근시의 경우 -0.52±0.48 D로 근시의 증가를 보였고, 원시의 경우 0.81±0.34 D로 원시의 감 소를 보였다. 근시의 경우 동공크기에 따라 등가구면굴절력이 -0.23±0.23D(3.0mm에서 4.5mm)와 -0.29±0.30 D(4.5mm에서 6.0mm)로 변하였다. 근시에 있어서 등가구면굴절력 변화량은 나이가 증가할수 록 많았다(p=0.008). 결 론: 동공 크기의 증가로 인해 안구 굴절력은 근시안의 근시를 증가시키고 원시안의 원시는 감소하는 것으로 나타났다. 상관분석 결과 나이가 증가할수록 암소시일 때의 동공크기 변화가 작아지고 근시일 때의 굴절력 변화가 많은 것으로 나타났다
        4,000원
        326.
        2016.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted the comparative analysis on quality and rice bread process suitability properties by four particle size classification of dry-milled flours for four rice varieties. Dry-milled rice flours were prepared by dry milling and classified according to particle size using 100, 150, 200, and 250 mesh sieves. The mean particle size by four particle size classification of 60 ~ 100 mesh, 100 ~ 150 mesh, 150 ~ 200 mesh, 200 ~ 250 mesh exhibited 118.9 μm, 87.4 μm, 65.3 μm, 46.1 μm, respectively. The particle size of dry-milled rice flours was the finer, the damaged starch content was the higher (r = − 0.570*). The particle size also had significant negative correlation with the water absorption index (r = − 0.533*, r = − 0.593*), and water solubility index (r = − 0.857**, r = − 0.584*). Dry-milled rice flours with particle size of 60 ~ 70 μm, passed through 150 and 200 mesh sieves exhibited the highest specific volume of rice bread. Whereas, the dry-milled rice flour with finer particle size above 200 mesh showed the lowest specific volume of rice bread. These results will be applied as a quality standard to aid in the selection of the most suitable dry-milled rice flour for baking.
        4,000원
        327.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to analyze fishing capacity and bycatch by mesh size and entrance size of spring net pot conductedby water tank and field experiment. The water tank experiments were conducted by using traps with mesh size of 22 mm and entrance size of 120 mm and 140 mm, respectively in the water tank of NIFS. The field experiment was conducted using 5 kinds of spring net pot with mesh sizes of 20 mm, 22 mm, 35 mm and entrance size of 120 mm, 130 mm, 140 mm, 360 mm by coastal trap fishery vessel operating around the area of Geoje island. In the result of water tank experiments, the catch of conger eel was 1.5 times higher when using trap with entrance size of 140 mm than that of 120 mm. In the field experiment, when using same mesh size, the larger the entrance size, the higher amount of conger eel catch, bycatch and number of bycatch species. When using the same entrance size, the larger the mesh size, the lower amount of conger eel catch and number of bycatch species, whereas the amount of bycatch showed increasing trend.
        4,000원
        328.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study primarily focused on evaluating the performance characteristics of 4.75-mm nominal maximum aggregate size (NMAS) asphalt mixtures for their more effective implementation to a layered flexible pavement system. METHODS: The full-scale pavements in the FDOT’s accelerated pavement testing (APT) program, including 4.75-mm mixtures at the top with different thicknesses and asphalt binder types, were considered for the faster and more realistic evaluation of the rutting performance. The results of superpave indirect tensile (IDT) tests and hot-mix asphalt fracture mechanics (HMA-FM) based model predictions were used for cracking performance assessments. RESULTS: The results indicated that the rutting performance of pavement structures with 4.75-mm mixtures may not be as good as to those with the typical 12.5-mm mixtures, and pavement rutting was primarily confined to the top layer of 4.75-mm mixtures. This was likely due to the relatively higher mixture instability and lower shear resistance compared to 12.5-mm mixtures. The energy ratio (ER) and HMA-FM based model performance prediction results showed a potential benefit of 4.75-mm mixtures in enhanced cracking resistance. CONCLUSIONS : In relation to their implementation, the best use of 4.75-mm mixtures seem to be as a surface course for low-trafficvolume applications. These mixtures can also be properly used as a preservation treatment that does not necessarily last as long as 12.5-mm NMAS structural mixes. It is recommended that adequate thicknesses and binder types be considered for the proper application of a 4.75-mm mixture in asphalt pavements to effectively resist both rutting and cracking.
        4,000원
        329.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목 적 : 확산강조영상은 뇌신경계에서 ischemia, infarction, inflammation, infection, tumor등 다양한 병변을 진단하는데 유용하다. 하지만 척추 확산강조영상은 심장의 운동, 호흡이나 연하에 의한 움직임과 척추체가 가깝게 있어 자기화율의 급격한 변화 등의 이유로 distortion과 artifact가 많이 발생하여 좋은 영상을 획득하기 어려웠다. 확산강조영상에서 영상의 distortion과 artifact를 변화시킬 수 있는 인자는 SENSE factor와 voxel size이다. 따라서 본 논문에서는 흉추 확산강조영상에서 SENSE factor와 voxel size를 변화시켜 영상을 획득 후 이를 비교평가 하고, 영상의 distortion, artifact 줄여 진단적 가치를 높이는 것이 본 논문의 목적이다. 대상 및 방법 : 척추질환이 없는 건강한 지원자 10명(남자: 7, 여자: 3, 평균연령: 29.6세)을 대상으로 하였다. 검사장비는 Ingenia 3.0T MRI (philips medical system, Netherlands)를 사용하였고, 신호수집 코일은 DS posterior coil을 사용하였다. FOV 240×184, B-factor 0, 1000 s/mm², slice thickness 4 mm, NEX: 10, TR과 TE는 장비에서 제공하는 가장 짧은 값을 사용하고 SENSE factor를 1, 2, 3으로 설정 후각 SENSE factor에서 voxel size를 1×1, 2×2, 3×3 mm로 변화시켜 영상을 획득하였다. 정량적 평가는 T2/SAG영상을 기준으로 Thoracic Spine 6th body에서 spinal cord까지의 거리를 각각 측정하여 distortion을 평가 하였고, 정성적 평가는 영상의학과 교수 1명, MRI 전문 방사선사 2명이 5점 척도로 영상의 artifact, distortion, 병변 검출 능력 등 전체적인 영상의 질을 비교평가 하였다. 통계적 유의성은 Wilcoxon signed rank test(SPSS 18.0K for windows)를 통해 검정하였고 p-value는 0.01미만인 경우에 통계적으로 유의하다고 판정하였다. 결 과 : 고정된 SENSE factor에서 voxel size 변화에 따른 distortion의 정량적 평가결과 SENSE factor 1에서 voxel size가 1×1, 2×2, 3×3으로 변화할 때 기준점에서 측정한 10명의 지원자의 평균길이는 6.54 mm, 5.33 mm, 4.79 mm, SENSE factor 2에서 평균 4.22 mm, 3.33 mm, 3.14 mm, SENSE factor 3에서 평균 3.04 mm, 2.63 mm, 2.29 mm로 측정 되었다. 동일한 SENSE factor에서 voxel size가 3×3일 때 영상의 distortion이 가장 많이 감소되었으며 동일한 voxel size에서는 SENSE factor가 3일 때 영상의 distortion이 가장 많이 감소되었다. 정성적 평가에서는 distortion, artifact의 발생정도와 척추체와 척수에서의 병변 검출 능력을 5점 척도(평가 불가: 1, 나쁨: 2, 보통: 3, 좋음: 4, 아주 좋음: 5)로 평가하였다. SENSE factor 1, voxel size 1×1, 2×2, 3×3으로 변화할 때 평균 2.23점, 2.30점, 2.33점으로 비교적 낮은 점수를 받았고 SENSE factor 2, voxel size 1×1, 2×2, 3×3으로 변화할 때 평균 2.86점, 4.20점, 4.13점, SENSE factor 3, voxel size 1×1에서 3.10점, 2×2, 3×3에서 평균 4.66점으로 가장 진단 가치가 높은 영상으로 평가되었다. 각각의 SENSE factor와 voxel size의 변화에 따른 영상의 distortion의 감소의 통계적 유의성을 알아보기 위해 Wilcoxon signed rank test로 검정한 결과 모두 p<0.01 로 나타났다. 결 론 : 확산강조영상은 뇌 질환에서 뿐만 아니라 척추와 spinal cord lesion을 감별하는데 매우 유용하다. 임상에서 Thoracic spine 확산강조영상 검사 시 본 논문에서 실험하여 얻은 결과처럼 SENSE factor: 3, voxel size: 2×2 또는 3×3을 선택하여 영상을 획득한다면 영상의 artifact, distortion이 감소되어 진단적 가치가 높은 영상을 만들 수 있을 것으로 사료된다.
        4,000원
        330.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper is concerned with the single vendor single buyer integrated production inventory problem. To make this problem more practical, space restriction and lead time proportional to lot size are considered. Since the space for the inventory is limited in most practical inventory system, the space restriction for the inventory of a vendor and a buyer is considered. As product’s quantity to be manufactured by the vendor is increased, the lead time for the order is usually increased. Therefore, lead time for the product is proportional to the order quantity by the buyer. Demand is assumed to be stochastic and the continuous review inventory policy is used by the buyer. If the buyer places an order, then the vendor will start to manufacture products and the products will be transferred to the buyer with equal shipments many times. The mathematical formulation with space restriction for the inventory of a vendor and a buyer is suggested in this paper. This problem is constrained nonlinear integer programming problem. Order quantity, reorder points for the buyer, and the number of shipments are required to be determined. A Lagrangian relaxation approach, a popular solution method for constrained problem, is developed to find lower bound of this problem. Since a Lagrangian relaxation approach cannot guarantee the feasible solution, the solution method based on the Lagrangian relaxation approach is proposed to provide with a good feasible solution. Total costs by the proposed method are pretty close to those by the Lagrangian relaxation approach. Sensitivity analysis for space restriction for the vendor and the buyer is done to figure out the relationships between parameters.
        4,000원
        331.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to investigate the effect of pen and group size on behavioral characteristics of Hanwoo steers. Forty-eight beef steers, all 15 months of age, were used in this study, and were assigned to 3 groups: control (4/35.28 ㎡), treatment 1 (8/70.56 ㎡), and treatment 2 (12/105.84 ㎡). In addition, behavioral characteristics were analyzed every 2 days in each month using CCTV cameras. Each behavior of the treatment group was observed significantly more frequently (p<0.05) than the corresponding behavior of the control group in summer, especially feeding behavior. In addition, no significant difference was observed between the treatment groups. Locomotion was observed for a significantly longer duration in the control group than in the treatment groups (p<0.05), and resting was observed for slightly longer in the treatment groups than in the control group. Fighting behavior, related to social status, was observed significantly more frequently in the control group than in the treatment groups (p<0.05). In winter, feeding behavior was observed for a significantly longer duration in the control group than in the treatment groups (p<0.05) On comparing the behavior of Hanwoo steers during different seasons, we found that the steers showed more resting behavior during summer and more feeding behavior and movement during winter. The above results suggest that the behavioral characteristics of Hanwoo steers depend on the pen and group size, based on the higher frequency of fighting, rubbing, and scratching observed in the treatment groups than in the control group. The results also suggest that the behavioral characteristics of Hanwoo steers depend on the environmental conditions, as shown by the seasonal differences in behavior. Under conditions of high temperature stress, Hanwoo steers showed increased lying down, drinking and grooming behavior to counter this stress. The findings of this study can be applied to management practices for animal welfare and producticon of cattle in both growing and fattening periods.
        4,000원
        333.
        2015.11 구독 인증기관·개인회원 무료
        막 접초기용 최적의 중공사막을 탐색하기 위하여 기공구조 및 기공도를 제어하여 중공사막을 상전이법으로 제조하였다. 상전이법으로 제조한 중공사막의 기공구조는 도프용액의 용매와 내외부응고제의 상호작용에 의해 결정되며, 용매와 응고제를 달리하여 제조한 중공사막의 특성을 비교하였다. SEM 이미지를 통해 기공구조를 확인하였으며, 기체투과도 측정실험을 통해 기공도 및 기공크기를 계산하였다. 막 젖음 현상을 방지하기 위해 금속산화물의 친수성표면을 소수성으로 개질하였으며, 최소침투압력을 측정하여 기공도 및 기공구조에 따른 소수성 특성을 비교하였다. 또한 실제 이산화탄소 흡수 실험을 통해 기공도와 기공크기가 흡수특성에 미치는 영향을 분석하고 최적화된 중공사막을 탐색하였다.
        334.
        2015.11 구독 인증기관·개인회원 무료
        In this work, uniform and nanosize(75nm) silicalite-1 crystals was hydrothermally synthesized by using 9TPAOH:0.16NaOH:25Si:495H2O solution at 80 ℃. They were applied as seed in the secondary growth process for preparing silicalite-1 membrane by template-free method. The highest ethanol/water separation factor of 119 with flux 0.58kg/m². Furthermore, these membranes (nano seed, template free silicalite-1 membrane) exhibit high permselectivity of He over SF6(123), and small gas permeation mechanism and Knudsen diffusion studies suggest that the membranes contain negligible intercrystalline or non-zeolite pores.
        335.
        2015.10 구독 인증기관 무료, 개인회원 유료
        The single vendor single buyer integrated production inventory problem with lead time proportional to lot size and space restriction is studied. Demand is assumed to be stochastic and the continuous review inventory policy is used for the buyer. If the buyer places an order with lots of products, then the vendor will produce lots of products and the products will be transferred to the buyer with equal shipments many times. Mathematical model for this problem is defined and a Lagrangian relaxation approach is developed.
        3,000원
        339.
        2015.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 설악산국립공원에 서식하는 멸종위기종 산양과 서식지의 보전 및 관리를 위해 산양의 분변 및 카메라 트랩을 이용한 개체수와 서식지 이용 분석을 2010~2014년 동안 수행하였으며 생태학적 조사 방법(흔적조사, 카메라트 랩조사)을 사용하였다. 분변 조사와 카메라트랩핑 분석 결과 각각 166개체 및 251개체의 산양이 설악산국립공원에 서식하고 있는 것으로 나타났다. 흔적조사(분변)를 통한 서식지 이용 특성 분석에서 산양은 경사도 35°~60°, 고도 600~700m, 향 북동, 수계와의 거리 0~50m, 도로와의 거리 300~600m, 활엽수림을 가장 선호하는 것으로 나타났다. 카메라트랩 조사를 통한 산양 개체군 구성, 주간(07-18시)이 56.5%, 야간(18-07시)이 43.5%로 산양의 활동성을 파악하 였다. 이러한 산양의 개체수와 서식지 이용 특성 분석은 향후 그들이 살아가는 서식지의 보전과 서식지의 관리를 위한 중요한 기초 자료로 활용될 수 있을 것이다.
        4,000원